1. Field of the Invention
This invention relates to a waste ink reservoir for an ink jet printer, for storing waste ink generated by cleaning of a print head, and an ink jet printer incorporating the waste ink reservoir.
2. Prior Art
A print head for an ink jet printer is prevented from being clogged due to dried ink by sucking ink droplets from all ink nozzles of the print head (cleaning) or ejecting ink droplets from the same (flushing) prior to a printing operation. The waste ink sucked or delivered from the waste ink is received by a head cap, and introduced into a waste ink reservoir comprised of a waste ink container and a waste ink absorber filled in the container.
For instance, in a waste ink reservoir disclosed in a Japanese Laid-Open Patent Publication (Kokai) No. 9-300656, a waste ink absorber formed by a laminate of six ink absorbent boards is received in a waste ink container. Top two of the six ink absorbent boards are each formed with a cut-out portion at an end thereof, whereby ink is caused to drop (flow down) from a lower end of a waste ink tube brought to a position above the cut-out portion. That is, waste ink which is relatively low in viscosity is caused to be absorbed from an intermediate portion of one end of the waste ink absorber to all area thereof. This makes it possible to store a sufficient amount of waste ink corresponding to a service life of the ink jet printer, by using a relatively small container.
In the case of such a conventional waste ink reservoir, waste ink is always dropped to the cut-out portion of the waste ink absorber (portion facing the cut-out portion), and at the same time, from this portion, it is absorbed into all area of the waste ink absorber. The waste ink dropped to the cut-out portion once stays at the cut-out portion and then it is absorbed progressively. Therefore, the surface of the waste ink is dried, and a portion highly viscose and hence hard to be absorbed adheres to the cut-out portion. This occurs repeatedly, from which clogging of the cut-out portion can result. Clogging of the cut-out portion prevents the waste ink from being absorbed by the ink absorber, so that before the ink absorber is saturated with the waste ink, the waste ink can brim over the waste ink container.
It is a first object of the invention to provide a waste ink reservoir which permits waste ink to be absorbed by a waste ink absorber uniformly and efficiently.
It is a second object of the invention to provide an ink jet printer incorporating a waste ink reservoir which permits waste ink to be absorbed by a waste ink absorber uniformly and efficiently.
To attain the first object, according to a first aspect of the invention, there is provided a waste ink reservoir for an ink jet printer having a print head, comprising:
a waste ink absorber having a top surface, for receiving waste ink from the print head at the top surface, and then absorbing the waste ink for storage therein,
the waste ink absorber having vertically laminated layers of a plurality of ink absorbent boards each formed with a through hole vertically extending therethrough, and arranged such that vertically adjacent through holes of ones of the ink absorbent boards at each pair of respective adjacent layers are displaced from each other, thereby allowing the adjacent through holes to partially communicate with each other; and
a waste ink container accommodating the waste ink absorber.
According to this waste ink reservoir, waste ink flowing (dropped) down onto the top surface of the waste ink absorber (top surface of an ink absorbent board at an upper most layer) once spreads thereon, and then it is gradually absorbed by the ink absorbent board. As the waste ink spreads over the top surface of the waste ink absorber, part thereof flows down through the through hole of the ink absorbent board onto a top surface of an ink absorbent board at an immediately lower layer. If the amount of waste ink is large, the waste ink flows down onto top surfaces of ink absorbent boards at even lower layers, as if it flows down stair steps, while being gradually absorbed by each ink absorbent board. As a result, the time over which waste ink stays on the top surface of the ink absorber is reduced, and drying of part thereof is suppressed, while being brought into contact with a large area of the ink absorber and uniformly absorbed there from. This reduces the possibility of clogging of the waste ink absorber by the dried waste ink.
That is, waste ink constantly flows without stopping or remaining at a place, until it is absorbed by each ink absorbent board, and further it is brought into contact with a waste ink absorber in a wide area to be uniformly absorbed as a whole, which makes it possible to sufficiently prevent the waste ink absorber from being clogged by waste ink. This enables waste ink to be uniformly and efficiently absorbed by the waste ink absorber, and hence the ink jet printer itself can be designed compact.
Preferably, ones of the ink absorbent boards located at respective odd-numbered layers have respective through holes each formed at a horizontally identical position and having an identical shape, and ones of the ink absorbent boards located at respective even-numbered layers have respective through holes each formed at a horizontally identical position and having an identical shape.
According to this preferred embodiment, identical ink absorbent boards can be used for odd-numbered layers, and other identical ink absorbent boards can be used for even-numbered layers. This contributes to reduction of manufacturing costs.
Alternatively, each of the plurality of ink absorbent boards has the through hole formed at an identical position offset from a center thereof and having an identical shape, ones of the plurality of ink absorbent boards at respective even-numbered layers are laminated in a vertically reversed and/or horizontally reversed relationship with respect to each of ones of the plurality of ink absorbent boards at respective odd-numbered layers.
According to this preferred embodiment, identical ink absorbent boards can be used for all the layers, simply by reversing the top and bottom sides, or the left and right sides, and this contributes to reduction of manufacturing costs.
Preferably, the vertically adjacent through holes of absorbent boards at the each pair of respective adjacent layers are different in number from each other.
According to this preferred embodiment, the direction of flow of the waste ink flowing down as if on stair steps can be more easily deranged, whereby the waste ink can be fully spread onto the top surface of each ink absorbent board.
More preferably, the number of through holes of an ink absorbent board at a lower layer is larger the number of through holes of an ink absorbent board at an upper layer.
According to this preferred embodiment, the lower layer where the smaller amount of waste ink flows down is brought into contact with the waste ink at more dispersed areas thereof, which enables the waste ink absorber to uniformly absorb the waste ink at the whole area thereof.
Preferably, the waste ink absorber further includes a lowermost laminated layer of an ink absorbent board having no through hole.
According to this preferred embodiment, waste ink dropped onto a portion of the ink absorbent board at the lowermost layer through the through hole of the upper layer fully spreads on the surface of the ink absorbent board, which enables the waste ink to be efficiently absorbed thereby.
To attain the first object, according to a second aspect of the invention, there is provided a waste ink reservoir for an ink jet printer having a print head, comprising:
a waste ink absorber having a top surface, for receiving waste ink from the print head at the top surface thereof, and then absorbing the waste ink for storage therein, the waste ink absorber having:
vertically laminated layers of a plurality of ink absorbent boards each formed with a through hole vertically extending therethrough, a through-type ink absorber fitted through the through hole of each of the plurality of ink absorbent boards such that the through-type ink absorber extends through the plurality of ink absorbent boards, the through-type ink absorber being formed of a material which has a permeability sufficiently higher in a vertical direction than in a horizontal direction, and
a waste ink container accommodating the waste ink absorber
According to this waste ink reservoir, the top surface of the through-type ink absorber which is excellent in permeability in a vertical direction is exposed at the top. Therefore, as the waste ink dropped onto the top surface of the ink absorber (top surface of an ink absorbent) flows and spreads over the top surface, it is absorbed by the through-type ink absorber, and further, through the through-type ink absorber, absorbed by the ink absorbent boards at the respective layers. This reduces the time over which the waste ink stays on the top surface of the waste ink absorber, and at the same time, it is uniformly absorbed by the whole waste ink absorber. This prevents the waste ink absorber from being clogged by the waste ink.
To attain the second object, according to a third aspect of the invention, there is provided an ink jet printer comprising:
a print head for delivering ink therefrom; and
a waste ink reservoir including:
a waste ink absorber having a top surface, for receiving waste ink from the print head at the top surface, and then absorbing the waste ink for storage therein,
the waste ink absorber having vertically laminated layers of a plurality of ink absorbent boards each formed with a through hole vertically extending therethrough, and arranged such that vertically adjacent through holes of ones of the ink absorbent boards at each pair of respective adjacent layers are displaced from each other, thereby allowing the adjacent through holes to partially communicate with each other; and
a waste ink container accommodating the waste ink absorber.
To attain the second object, according to a fourth aspect of the invention, there is provided an ink jet printer comprising:
a print head for delivering ink therefrom; and
a waste ink absorber having a top surface, for receiving waste ink from the print head at the top surface thereof, and then absorbing the waste ink for storage therein,
the waste ink absorber having:
vertically laminated layers of a plurality of ink absorbent boards each formed with a through hole vertically extending therethrough,
a through-type ink absorber fitted through the through hole of each of the plurality of ink absorbent boards such that the through-type ink absorber extends through the plurality of ink absorbent boards, the through-type ink absorber being formed of a material which has a permeability sufficiently higher in a vertical direction than in a horizontal direction, and
a waste ink container accommodating the waste ink absorber.
According to these ink jet printers, the waste ink absorber within the waste ink reservoir is not likely to be clogged, and the capacity of the waste ink container of the waste ink reservoir can be used without waste. This permits the waste ink container (waste ink reservoir) to be designed compact, and hence permits the ink jet printer itself to be designed compact, while preventing leakage of waste ink into the apparatus.
The above and other objects, features, and advantages of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.